The party leaders’ televised election debates could take place up to a year
before the next polling day.

Senior politicians are becoming increasingly concerned that the exchanges will dominate the campaign for power in 2015.

Sir Menzies Campbell, the former Liberal Democrat leader, said the debates ahead of the next election should not be concentrated in the short three or four weeks of full campaigning after Parliament has been dissolved.

He backed concerns, already expressed by David Cameron, that the debates can “suck the lifeblood” out of the general election campaign.

Earlier this month, the Prime Minister indicated that the next set of leaders’ debates could be organised differently from the first televised exchanges in 2010.

Talks between the three main parties and broadcasters have begun but no agreement has been reached.

Sir Menzies told BBC Radio 4’s World this Weekend that he was “sympathetic” to the idea that the leaders’ debates could be held earlier.

Next year “might be a bit early, but certainly in 2014 – I can’t see any objection to that,” he said.

If the debates are held during the short month of full campaigning, political the “whole focus” of political parties is on the debates “and that inevitably sucks the lifeblood out of the general election campaign”, he said.

An early series of televised clashes between the three party leaders could be the best way to begin the “amicable” process of ending the Coalition between the Lib Dems and the Conservatives, he suggested.

“Everybody knows this Coalition’s going to come to an end, and I’m one of those who says look, we should be quite open about that,” he said. “Perhaps these debates would be the first way to begin that.”

Lord Howard, the former Conservative leader, said he did not understand the complaints that the debates damaged political campaigning.

“I’m not sure what evidence there is for this supposed belief,” he said. “I think it would be very difficult to row back from the fact that we have now had televised debates, I think they were very successful.”

He said the amount of time between debates was up for negotiation, and should not be used as an excuse to scrap the whole programme.

While it is assumed that they will now become a fixture of British elections, as they are of American presidential elections, no agreement has been made for the next set of debates.

Mr Cameron said earlier this month that he found the format for the 2010 series of debates too “controlled”. Audiences were banned from applause under a set of highly restrictive rules.

Mr Cameron told journalists before Parliament broke up for the Christmas recess that he supported the TV debates and “enjoyed them last time”.

“We have a fixed-term Parliament now, so we can think about it in a slightly different way,” he said. “I haven’t made my mind up exactly what we should do. My reflection on last time was that they did take all the life out of the campaign.”